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Date: Wed, 01 Aug 2012 16:55:53 +0800
From: Cong Meng <mc@linux.vnet.ibm.com>
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Subject: Re: [Qemu-devel] [PATCH] add suport for ATA_PASSTHROUGH_xx scsi
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To: ronnie sahlberg <ronniesahlberg@gmail.com>, Paolo Bonzini <pbonzini@redhat.com>
Cc: zwanp@cn.ibm.com, linuxram@us.ibm.com, stefanha@linux.vnet.ibm.com, qemu-devel@nongnu.org

I see. thank both.

On Wed 01 Aug 2012 04:49:18 PM CST, ronnie sahlberg wrote:
> Because opcode 0xA1 has a different meaning for CDROM/MMC devices.
> On such devices 0xA1 means BLANK, so it would collide if QEMU some day
> adds support for
> re-writeable mmc device.
>
>
> On Wed, Aug 1, 2012 at 6:45 PM, Paolo Bonzini <pbonzini@redhat.com> wrote:
>> Il 01/08/2012 10:43, Cong Meng ha scritto:
>>>>
>>>> Please make this conditional on the type _not_ being TYPE_ROM.
>>>
>>> May I ask why cdrom device should be an exception?
>>
>> Because CD-ROM devices do not support ATA PASSTHROUGH (the SAT standard
>> only describes direct access devices---type=0x00).  The 0xa1 command is
>> "BLANK" for CD-ROMs.
>>
>> Paolo
>>
>